I have a wood chimney enclosure through a 12 on 12 asphalt shingle roof. It has an exterior backer board/stucco finish. It has a cricket with step flashing and counter flashing, but leaks at a lower corner closest to a dormer which is about 18" away. The step flashing extends up the chimney (on the wood) about two inches and about an inch down from the backerboard. The counter flashing covering the step flashing and extends up to the bottom of the backerboard. The step flashing is caulked at the top.
Can some one tell me if this a proper flash job?
Usually when I see crickets leak its because the bottom step doesn't extend past the corner enough, or at all. The bottom step flashing needs to pass the bottom corner of the cricket min 1/2", preferably more. A good roofer can make this look clean.
If it has metal valleys, the bottom of the valley needs to be bent up the wall, and pass the corner on the bottom as the step flashing would.